The invention relates to a throttling device for conduits, such as pipe conduits. In particular the invention relates to a pipe section including a flap valve rotatable by an adjustable drive. The pipe section and flap may be inserted in the flue between a furnace or boiler exit and a chimney.
Throttling devices provided with flap means have been known for a long time. These devices, however, have a drawback since the cleaning of the respective pipe sections of soot or dirt is substantially encumbered, because the passage of brushes or other cleaning means is obstructed.